The rotor is the rotating component in a Wankel engine that produces power. Combustion pressure pushes against one of the rotor’s three faces, causing the rotor to revolve inside a specially shaped housing.
Unlike a conventional piston engine, the Wankel has no reciprocating pistons, connecting rods, or conventional crankshaft. The rotor continuously forms three moving chambers that perform intake, compression, combustion and exhaust. Its three-sided shape and the housing’s epitrochoid curve keep those chambers separate as the engine turns.
The rotor does not deliver power directly to the vehicle’s transmission. Its motion is transferred through an eccentric lobe on the eccentric shaft, which acts as the engine’s output shaft. The rotor turns at one-third of the eccentric shaft’s speed, while a synchronizing gear keeps its movement correctly aligned with the housing.
Felix Wankel developed the rotary principle, and NSU brought it to production in the 1960s. Mazda became its best-known long-term user, applying rotary engines in cars such as the 1967 Cosmo Sport and later RX-7 models. The eccentric shaft is therefore crucial, but the rotor is the power-producing working component.